1978 F250 400 Dual Fuel

[Provience]

got the wideband hooked up over lunch, stupid simple to do with a nest of wires hanging under the dash, found a keyed hot and a keyed ground (why isn't it straight ground? I dunno) just hanging out.

this thing is fun to play with. Turns out, i'm lean as taylor swift all over the damn place. idle was pretty close and i tweaked it a bit to get ~13.7 at just over 2-1/2 turns out. apparently the o2 is less useful at idle due to the lower airflow and it does move around a bit, off idle it's much more stable. Opened the edelbrock book and they suggest 13.0 is a "typical" idle, guess i'll try out more rich later and see what it does to RPM and vacuum.

light throttle cruise is about 15, medium acceleration is about 16-17 and WOT is 17+ Saw 22 briefly before the gauge maxed out. Just for kicks I went and adjusted the accel pump shot to max from mid and at WOT it now briefly drops to 13.5 before going back to ~17. no bueno and it's solidly a lean stumble at the top end.

no detectable misfire in the 16+ range so i'm not going to assume that it is a rich fouling or dead cylinders or massive air leak causing the lean reading.

i was hoping that i'd be somewhat close and able to get away with just buying a couple jets/needles, but at this level i'm going to spring for the $75 kit and take the full compliment.

edit:

hard to take a picture, after driving home on the highway, went ahead and richened up and reset idle. 650 RPM at 12.9-13.3 range to see if that would make much difference in cruising, not particularly during a quick trip around the block

sitting here with no load, this is very light throttle and maybe 1500 rpm, goes right up to 16.2ish range

and still no load but opening up the throttle even further, it'll come down to just under 14.7. this must be the point where the "power" portion of the rod is coming in to play. for having no load, not good.

cruising the highway at very light load and 60-65 mph it would drop similarly into low 14's, makes me think i'm cruising on the power circuit instead of the cruise circuit, and so i'm leaning toward going a couple steps more rich on cruise, at least 1 step more rich on power and probably a weaker spring so that the transition between the two will come in later and keep me on the cruise circuit longer on the highway.

tomorrow my tach and vacuum gauge should arrive and get hooked up and those will help dial things in my head before actual parts arrive and we get to find out if i'm completely off the rails or if making a change moves things in the right direction and helps out with powa!

 

[[486]]

take some sandpaper to the rods and the torch tip cleaner to the jets

 

[Provience]

take some sandpaper to the rods and the torch tip cleaner to the jets

that'll be when i need to tune it up for altitude

might have to take one of the small jets and just drill that bitch out a wee bit more

edit tag for later: Everything You Wanted to Know About Vacuum Advance and Ignition Timing

 

[Provience]

alright, underhood tuning with the timing and the vac. gauge - goal is to get the highest vacuum and rich until it quits increasing the idle, this had me at about 2-3/4 or 3 turns out and just back down into the 12's according to the AFR. It was pretty darn happy at 20 inches and 650-700 rpm.

also, turns out that both of my vacuum ports off the front of the carb are "ported" when it should be one full, one ported, so i'm not getting any real vacuum advance at idle but it comes in just off idle. maybe i need to turn the idle up a bit instead of the factory 650 recommendation and play with that to see if it is just too low to let the port below the throttle blades. i dunno, more looking into it required.

well that picture didn't really work out

and any vehicle worth it's salt in 2021 has a center mounted infotainment system

fits in pretty well with the theme of the trucks interior

one of these days i'll learn which way is up on the phone. handheld data log, watch the vac gauge and tach for an idea of throttle position, runs 1,2,3 trying to be more aggressive and "see" if I can catch the Power circuit spring cutoff richen everything up on the AFR.








also, if anybody is wonder what it's like to drive with the transmission hooked up to a ported vac reference, strange is the answer

 

[Provience]

3 steps backwards, half a step forward

got stuff in the mail today

went and made a vacuum splice tree so that the gauge, transmission and dist. will all work at once. according to the internet, the vacuum plug on the manifold should be 3/8" NPT. I'd like to put a barb fitting on the plug on runner #5 as it's right next to the carb, and keep the rear one for the trans and gauge. that's some cleaning up the wiring type stuff though

Sometimes I wonder about how much of my lean condition is caused by poor airflow due to this hat. Wife suggested getting a standard air cleaner for it for now, and then once it's decent running on gas and after the rest of the propane system is rebuilt, putting it back on. Probably a good idea.

overhead shot

didn't have an issue with it on the bench, for some reason the pass side rod doesn't want to pop up

and top off

and then a whole bunch of Go Fuck Yourself whatever step up springs were in there before felt much softer than most of the springs in the kit. went ahead and put the orange 5" springs in, and swapped the 0.301" primary jet for a 0.304" primary jet while reusing the same rod. i.e. full rich #18 on the chart a couple posts up.

and then I accidently hit the fuel cutoff and ran it dry...then it wouldn't restart. took a while to figure out WTF was wrong, apparently the fuel solenoid just shit locked up, I dunno, but it's all bypassed with a hack job of close enough not-fuel rated lines to work for now

anyways, took it for a drive and grabbed another sideways video. it's now good enough on the cruise side that i can accelerate enough for the transition springs to lift and then it goes way rich. Seems fairly obvious when the transition is, at least more obvious than with the previous setup. seems interesting that the 5" rated spring seems to lift at 12-14" on the gauge, but whatever, it's all relative to something anyways and is possible the vacuum at the carb base is different than at the gauge ~6' of hose away, especially on the quick blip. i'm going to try and drive it to work tomorrow and see how it does





edit: alright, trial #2 is "point 17" using a 7052 rod, and i went ahead and kicked down to the yellow 4" vac spring to delay it a bit. very short down the driveway and back and it seems to be really going in the correct direction still can't get to WOT, but getting closer

edit2: tagging this to read later Carb Science Series: Holley Power Valves — Explanation And Tuning yeah it's for a holley, but i'm curious about where they are tuning in the power circuit

edit3: moved the pump shot from middle to top "max" hole over lunch today, point #17 seems to drive and cruise much better than previous, still stumbles lean and won't get over that hump to get heavy/WOT. going to observe on my drive home if this extra juice helps out with that. it seems to be getting closer and the driveability is much improved, thinking i'll try leaning out idle screws again to go from mid-high 12's to mid-high 13's if this continues. i'm looking forward to being able to get into the secondary jets and even see if they are fat/lean.

 

[Provience]

welp, swapped back from the 7052 rod to the 7047 rod again, using the yellow spring instead to see if it will richen up enough to let me get to WOT so that i can try and guess if the secondaries need more or less.

and then while poking around, noticed that the secondary butterflies aren't actually opening turns fucking out that despite the choke being where it thinks it's fully open, it was still hanging up enough to keep them closed. - and suddenly, the world got a whole lot brighter

so went and just moved the choke counterclockwise/lean about 4 notches on the case and sumbitch, it will actually go WOT now Wildly different output.

I open/close the propane hat every time it comes apart to take the tension off the spring. the other day it was having issues inside the hat, today it decided to have issues inside the cab. final straw, and it's all now in the trunk with the cable just up and out of the way

and that was enough that i'm finally going to soak the spark plugs in PB blaster so that i can get them changed + new wires, so tomorrow should be a much better day of results for messing with things.

 

[KungFooMASTA]

Carb tuning? If it starts with anything less than half a can of ether and runs without dumping fuel all over and catching on fire its good enough for me.

 

[Provience]

Carb tuning? If it starts with anything less than half a can of ether and runs without dumping fuel all over and catching on fire its good enough for me.

this is half the reason i was excited to get rid of my EFI rigs learning a ton, probably going to make a spinoff thread in newb 4x4 once i get it actually going good and put my thoughts in order

edit: depending on where you buy your carb from, i'm still just under the price of a new one so i've got that going for me well cheaper than efi swap, even a junkyard TBI setup

 

[Provience]

alright, now that everything is hooked up and new spark plugs are in place, got a chance to do a little bit of cruising.

first things first, stickers

and the old spark plugs

left to right 1-4

left to right 5-8

and some cut to fit plug wires. beats the ever loving fuck out of me where the correct hei ends for these went, so i used the regular style and at least one would come loose after each run so the old ones are back in place now

 

[Provience]

and some more sideways videos.

this is what we started with, spot # 18 from above. 0.104" primary with 70/47 rod, yellow 4" spring, 0.095" secondary. rolling on the throttle from a stop



same setup as above, but WOT from a stop



and from there moved down a jet to spot #15, still 0.104" primary with 73/47 rod



after that, figured i'd go leaner again. this isn't quite spot 9 as the carter came with a 0.101" primary jet instead of 0.100", so i'm a touch more rich.

0.101" primary with 68/42 rod



it drives pretty dang good like that, for some reason it is absolutely idling like shit now at very first, my HVAC vacuum can was causing a massive leak, so i've unhooked that. now it is still acting like it has a vacuum leak at idle, which it never had before, and it is creating some mis-fires and all kinds of drama. i dunno, cleans up a bit with time, but still isn't nearly as smooth as it was before, like yesterday

tomorrows problem for sure

edit: after watching the last video with "tuning spot #9" a bit more deliberately, I think i'm going to try and keep what I have there and swap out the yellow 4" spring for a pink 7" spring and try the slow roll run again. at about 2500 RPM and just above 10" of vacuum, it's leaning out to high 15's low 16's which is more lean than i'd like to be for accelerating right there. at about 6" of vacuum, after the trans shifts, the AFR starts dropping and is low 13's by about 4". that's what i'd like to see and using the 4" spring makes it easier to tune the cruise circuit as i know i'm not in my power circuit. if 4" worth of springs starts influencing at 6" of vacuum, then hopefully 7" spring will influence near enough to 10" of vacuum that it will make the transition of bit more gentle from cruise to power on the rod. and then, if that works out, i'll be able to check the secondary. Near the end of the video i'm WOT (guess i'll need to make sure the pedal gets all the way there as the manifold still shows a little bit of vacuum) and it drops to 11.5 AFR. that is probably more rich than needed for an all-in type of deal. Playing with the spring will give me a better idea if the issue is my secondary jet or my "power" circuit on the small diameter of the metering rod.

personally leaning towards dropping the secondary from 0.095 to 0.092 then 0.089 to hopefully confirm that 0.092 is the way to go

This thing cruises the highway at 70mph under 3k rpm and over 10" of vacuum, so i want to be careful that i don't run too much spring and fall into the "power" circuit while i'm trying to cruise


edit: after watching the WOT video (second one from the top of this post) it's shfiting at 4k rpm. Sure I have the kickdown unhooked and set at off, basically, so i'll wait to get that done up first. but hell, if it won't shift above 4k, we are going to have problems with this transmission

c6 trans won't shift when kickdown is connected

www.460ford.com

a thread talking about adjusting the vacuum modulator vs changing the pins vs shaving the governor.


edit: note on playing with trans shift points, usind the peak TQ and HP spots for the Crower 15170 cam on a 400 engine and stock gearing and the grim jeeper calc, shift at 4,800 RPM at WOT would give me a 2-3 shift at 79/80 MPH and drop from 4.8k to 3.3k. Peak TQ from the cam is about 3k and HP at 4.5k. that would about be my max and would let me run a second gear uphill as fast as i could really ever want to go

it would also put me cruising 65 mph at 2,700 rpm and just below peak TQ, as opposed to stock where I was already past peak TQ at highway cruise.

 

[Provience]

same jetting and everything spot #9 on the big chart, just a spring change from Yellow 4" to Pink 7". similar to the orange, it "feels" like the pink is coming in earlier than anticipated according to the gauge whereas the yellow seemed all in more as advertised.



and then leaned out the power circuit, still using the pink spring, and also dropped the accel pump from max to mid, doing these slow roll from stop to WOT should keep the accel pump from having too much influence.



I dunno, i'm going to have to drive it like this for a day or maybe two with the commute and such to see how i feel about it. getting really close, might change the spring to orange (5") again, might lean out the secondary jets 1 stage.

edit: just changing from the -42 (piont 9) to the -52 (point 8) power circuit rod took my WOT AFR from mid 11's to low/mid 12's. makes me thing going 1 stage leaner on the secondary jets would be enough to get me to mid/upper 12's, but if doing that puts me into low 13's and not 12's at all, i'll go back to this configuration

edit2: readjusted the choke and swapped out 1 of the vacuum caps. idle isn't as smooth as i'd like but it's better than the crap i was getting the other day

edit3: alright, so just cruising around low speed and above 16" of vacuum, i'm about 16 AFR, which puts me about where i want to be for the idle circuit. cruising the highway at 65/70 mph i'm about 15" of vacuum and high 13's low 14's and WOT i'm dipping into mid/low 11's. does have a slight lean stumble right at the transition, so i'm going to go back to the top max spot for the accel pump shot to see if that clears up that, and then go to a 1 stage leaner secondary to see if i can get WOT back to the upper 11's mid 12's range. as long as that makes no change to the high vacuum cruise (or anywhere really) then i'll try 1 stage leaner cruise and 1 stage leaner power rods. that would be the 0.092" secondary first step and then 0.098 primary with 70-52 rod.


edit: this is a cool article for estimating HP based on 1/8 and 1/4 mile trap speed

Account Suspended

edit 67: changed just the secondaries to 0.092 (1 stage lean) and now i'm solidly 12.2 WOT, with some variance up to maybe 12.5, but not much on 2 long WOT pulls, and I seem to be 12.8-13.0 on the power circuit about 7" vacuum with 13.6-14 on the cruise circuit, above 15" or so cruising the highway at 55mph...so off to try out the 0.098 primary and 70-52 (point #21) also, the bog from the transition to WOT was worse with the max pump shot, going to leave it there for now and mess with it probably tomorrow if need be


edit42: Hesitation or Bog? the most detailed pump circuit explination that i've seen yet. for reference the 1405 uses a 0.028" nozzle and the 1406 uses a 0.031". i'm going to assume the carter has the 0.028" but i might pull it off and measure. biggest takeaway from the article: bigger nozzle = faster fuel dispense; arm hole adjustment impacts total fuel volume, regardless of nozzle; 800cfm+ uses stiffer spring, 750cfm- uses softer spring, stiffer spring means faster delivery. tune this circuit last.

also apparently the pump is a handy wear item, and should probably be replaced if you have to think about it.

stiffer spring + smaller nozzle = higher velocity, not sure what it would do to duration. anyways, there is a good chance i'll stick with what i've got now (point 21) but we'll know everything tomorrow.


edit671: driving in this morning, i'm pretty happy about it. bit of traffic today, but it 'seems' to cruise 60 mph about 15.5-16 at the 15" mark, drops down to 14.2-14.5 at 7" or so, then seems to be 12.2-12.5 at WOT. i'll probably go to the heavier 8" spring instead of the 7" spring for the drive home, and play with the pump shot over the next couple of days, otherwise i'm pretty happy with it. still about 13.5 at idle.

 

[Provience]

Took pictures while driving, steady cruise at 60 MPH. i'm happy with that

this was then accelerating, looks like the picture took after i had let off the throttle due to camera delay, but i was going 75 at this point. at a longer pull in the 6" vacuum range, it was holding around 14.2, the higher vacuum on the gauge, this is about 14", indicates i was off throttle, when going off the AFR either goes more rich or more lean depending on what is going on

and this was a WOT pull up a hill, looking at the gauge was 12.2 about the lowest steady, apparently 12.4 on the picture. I might try a 1 stage leaner secondary jet, but it's hard to ask for better than this

went with the 8" silver spring, no real loss and might be a tad better getting onto the power circuit earlier. still has a bit of a lean stumble on the transition to WOT, next step will be moving the pump arm to min shot and seeing if the bog is worse than having it on max to confirm that it is not a rich misfire, and after that will be going to the heavier spring pump.

odds are good that just a stock replacement pump would be better enougher as this one spent ~10 years on a shelf after very little use, but meh. might as well go whole hog and turn it down as needed if it's too rich. they both cost the same $15

 

[Provience]

regarding fuel mileage, while doing a bunch of testing and tuning on the carb I clocked 9.8 MPG, then drove it for a week just normal around town and commute stuff with a few light trailer loads and I was at 11.4 MPG.

which is about on par with the suburban, so i'm happy. still need to get the rear tank dropped and fully functional. using the single 19 gal tank is not enough

edit: using the odometer and the same gas pump of fill it until it shuts off. not the most accurate test in the world but about the only way i ever done it

 

[rockota]

So... uh... when you add all of your hours and your wife’s “you missed this, DA,” what is your “real world” mileage?

 

[rockota]

So... uh... when you add all of your hours and your wife’s “you missed this, DA,” what is your “real world” mileage?

 

[Provience]

So... uh... when you add all of your hours and your wife’s “you missed this, DA,” what is your “real world” mileage?

hours? bah! my time is worthless!

priceless?

Can't be valued! sounds about right

the only thing that really matters is that the motorhome goes about 400 miles on a tank so i'll need to get this onto that level, or close to it, full of shit and hooked to the trailer so that we are about on the same pace next spring when we move down to texas. i'm going to be gone for 7 of the next 9 months though, so trailer controller wiring and functioning dual fuel tanks are probably all that will happen between now and then. might change the oil before we leave, probably should try a flush/clean on the cooling system, just maybe grease the bearings in the truck and trailer.

so yeah, if i can manage double digits or high 9's on that trek i'm doing swell. especially after ya'll got me half convinced i'd be 6-8 with a tailwind using a non-lockup/auto/400 slug

 

[arse_sidewards]

hours? bah! my time is worthless!

priceless?

Can't be valued! sounds about right

the only thing that really matters is that the motorhome goes about 400 miles on a tank so i'll need to get this onto that level, or close to it, full of shit and hooked to the trailer so that we are about on the same pace next spring when we move down to texas. i'm going to be gone for 7 of the next 9 months though, so trailer controller wiring and functioning dual fuel tanks are probably all that will happen between now and then. might change the oil before we leave, probably should try a flush/clean on the cooling system, just maybe grease the bearings in the truck and trailer.

so yeah, if i can manage double digits or high 9's on that trek i'm doing swell. especially after ya'll got me half convinced i'd be 6-8 with a tailwind using a non-lockup/auto/400 slug

Just add tanks.

A ranger/sploder tank is tall and skinny to fit between those RBV frame rails without getting in the way of the driveshaft. The top is a big plastic screw on lock ring that makes it damn easy to stick in any fuel sender you want. Slap a pair of those outside your frame rails and you'll get 500mi no sweat.

 

[87manche]

fucking carburetors.

EFI the world.

 

[Provience]

fucking carburetors.

EFI the world

unrelated to the carb, i seem to have a mild vacuum leak somewhere that is slight and inconsistent. otherwise, i'm happy with the carb and still substantially below the cost of EFI gauges and everything considered.

 

[Provience]

needed to get my trailer lights and such figured out. Turns out, the issue was all on the trailer side and despite the interesting mess of wires on the truck, the truckside seemed to be fine. Spent way too much time the other day trying to figure out why a stop/turn light wouldn't go despite having 12volts at the plug. So now i've got new light buckets and new wires and mostly everything works correctly

Existing truck side

existing junction box, i'm pretty convinced all those splice connections were causing me a bunch of issues

I'm hoping this heavily damaged wire is the reason my brake controller doesn't work

and this was the left rear corner, it was fun that the wire colors changed a few times during the whole run all the way back

started at the truck, put in a new mount and plug, this has a little catch thingy on it that mates to the other side plug.

Chopped off several inches of the trailer side plug to get back to where the wires were still supple

aside from chopping off the end, i reused the front plug wire group, I did rewire it so that all the colors match up better. Picked up some 4strand bonded wire for the lights and used some 12 gauge that I already had to do the brake signal repair section. Sure it doesn't look as good as the heavily insultaed wires, but it was cheaper and easier

the clips that hold the wire on are in such bad shape that I left the old wire along the frame and just zip tied the bonded wires on top of them. seems to work....

Turn/brake lights are 2 wire flush mount 4". During lot's of testing yesterday, they benefited from direct grounding, so I went ahead and added a ground wire directly to the bulb housing instead of relying on housing ground through mounting screws to the haggard frame

4 wire bonded into the frame, then 4 wire bonded through the rear rail to the other side, parking lights in the corners and center mean there is a whole lot going on here, but i'm happier with it versus what was there before.

and now that the colors all match and line up, everything along the back works, except for one of the marker lights I broke, but the front marker lights now illuminate with the right blinker oh well, close enough.

this was t
he easiest to see diagram that I found at the top of my image search

 

[arse_sidewards]

The EMT box is a nice touch.

 

[Provience]

The EMT box is a nice touch.

hey man, it functions.

I hate almost everything about trailers, but several years ago when I got this it was "yup, needs a deck soon" and "I should really fix the rust on the cross bars" and exactly none of those things have happened since then

 

[Provience]

note taking.

Went out this past weekend and got to sit in the Audi that ProjectTwin built and it absolutely blew my mind in every way. seeing colors and shit. Build Log: 2006 Audi A4 Avant Stealth 24" sub build.

talked to several people there at the meet and greet and now I've got a new list compiled for when I eventually get around to redoing the interior on this thing (or whatever I happen to own when I am comfortable spending money on stuff)

Obviously I won't be super cool, but here is my current parts list for a mid-grade-hopefully-better-than-most stereo setup.

AudioControl D-5.1300 - currently $1,199 @crutchfield​

D Series 5-channel car amplifier with digital signal processing — 100 watts RMS x 4 at 4 ohms + 500 watts RMS x 1 at 2 ohms (300w @4 ohms)

JL Audio 10W0v3-4 - currently $180 @crutchfield​

W0v3 Series 10" 4-ohm subwoofer [5" mounting depth, 25-250 Hz response, 0.65 sealed box volume]

Kenwood Excelon KMM-X704 - currently $170 @crutchfield)​

Digital media receiver [6 pre-amp outputs @ 5v, will play hi-res files]

Sound Integrity 3.5" - currently $250 pre-order rather than $400. met Nick with SI, he gave me a tshirt so i should buy his stuff

M3 Carbon Midrange​

&

TM65 mkIV Midbass $350-400​

 

[[486]]

run it on propane yet?

 

[Provience]

run it on propane yet?

Nope, driven about 20 miles in the last 5 or so months.

Never have gone through the propane lines from the tanks up, hell never did fix the rear tank and regular fuel lines.

Going to be lots of fuel stops moving with it, but it'll be next summer before I can actually do anything, hopefully.

The way gas is going, I'll have to mess with the pane sooner rather than later

 

[Provience]

if i put 20 miles on it in the last 5 i'm up to about 25 miles in the last 9 months Thought this goo was kind of neat, came from the bottom of the fuel bowls. silly corn in my fuel.

Overall, not too bad. took off everything and sprayed until carb cleaner ran clean through all the holes. Also changed out the primary jets to 401 with 7052 rods (previously was 398 with 7052) and it seems to have helped all over.

also finally swapped out for the new 1468 heavy spring accel pump. I am still getting a lean misfire under load or quick acceleration, but it isn't as big or bad as it was before.

and just for kicks, replaced these sections of wire from the coil which are not in great shape.

 

[Provience]

alright, starting to figure out how easy or difficult this will be to get the aft (main) fuel tank to function.

Dash fuel gauge shows proper level with mid (aux) tank selected and runs fine.

Dash fuel gauge shows E always for aft tank. Put fuel in it a long time ago, it may be empty or not now.

While driving on Aux tank, I flopped it over to Main and made it about 2 miles before truck stalled and died, flopped back to aux and it was able to restart.

here is a snip of the wiring schematic for the fuel tank circuit. 973 R supplies 12v power from the fuse box, as ugly as the fuse is, it has 12v+ on both sides

I was curious how the valve/solenoid worked because it just has 1 wire running to it. Turns out the aft/main tank is selected with 0 volts and mid tank with 12v. Easy enough to check and sure enough i'm getting 10v+ trying to ground through the rusty frame when mid/aux is selected and basically zero V with aft/main selected.

Fuel Tank Sending Unit Tech - FORDification.com

more reading says the sending unit should be 70-73 Ohms (high) resistance when fuel level is E and 8-12 Ohms (low) when fuel level if F.

currently i'm getting ~120 Ohms, indicating the sending unit is faulty.

of course, when i attempt to ground the line to the frame it also doesn't send the dash gauge to full, so there is likely an issue in the wiring as well. Free things first, going to pull apart the dash and sand/clean plugs working back and see if that helps anything.

 

[Provience]

little bit more tinkering today

Dash coming out

fuel tank selector switch is only held in by the one bolt

Has some crusty on the outside, went to the store to buy fuses and bulbs to see if it would get the instrument cluster to light up. They wanted ~$90 for the damn thing worth taking apart and looking for that much money

after peeling up the tabs, the inside appears to have some rather old grease inside. playing with the gauge before taking it apart and it wasn't making good contact it seems.

cleaned all that up, at least it measures continuity easier on the meter now. no idea where all my electric grease is at, so back together dry for now

Took the dash over to the battery and sending 12v to the gauge results in Full, so it seems to be fine on that side of things.

went underneath and pulled off the solenoid, it clicks and selects successfully at the battery, all the lines seem to be open and proper through there. Opened up the fuel tank and apply very light air pressure to the hose side and can hear air, but no bubbles or anything. Either the pickup tube is very rotted or the tank is empty. Measuring the sender resistance to the actual ground on the sender results in ~70 ohms, which means the gauge is reading appropriate for an empty tank. Hooking it up and measuring to the dash netted ~85 ohms, so i went ahead and cut off the old ground to the frame and sent a new wire up to another ground in the dash.....now i'm getting ~100 ohms oh well, next thing is to go and toss a few gallons of fuel in there and see if it changes or works or whatever.

edit: just another note, when i pulled off the hose from the tank to the solenoid, it dropped a little bit of fuel on me. Was confusing at first, but it makes sense because with key off there is 0v to the solenoid so it is Open to the aft tank/lower input.

edit: probably mostly due to cleaning out the switch in the dash, but also maybe due to moving the ground up to the dash rather than thru the chassis, but sumbitch it actually works now. Put 3 gal of gas in the aft tank, some minor dripping while fueling, so i'll see what I can see about that, otherwise it registered about an appropriate amount and drove for long enough that i'm satisfied. Not sure i'll use it for day to day stuff until i get the slight leak figured out, but for soaking up highway miles i'm all about it

 

[Provience]

2k miles
15k lbs

And it pretty much all worked.

Door tag says 7900 lbs, sticker marks on the rocker panels said 8k lb gvwr, crossed the scales at 8k lbs on the truck and 7.2k lbs on the trailer.

How it started.

How it ended.

Tarps made it, just barely. Had to buy some extra straps along the way

200 miles away from being done, the exhaust tick from a couple days ago grew into a bubble. Lost some nuts and bolts at the collector.

Made it 100 miles like that before the tube dropped off. Found out that talking canceled out some of the noise in my head

First day, used the brakes a grand total of 8 times. Clearly the existing controller wasn't up to the task. Wired in the new one at midnight in a rest stop outside Boise ID. Turns out, the 12v battery wire in to the controller was not good. So I hack fabbed it into an unused fuse slot and held it in place with a spare fuse. Black wire new, white existing. Functional trailer brakes make a huge difference.

And also hacked in a USB outlet and newer lighter style outlet to charge phones and GPS

Otherwise, both fuel tanks worked great, the slow drip while fuelong even stopped. Worst tank was 6mpg, best tank was 9mpg most were about 7mpg. Almost exact same fuel used per gallon as the motorhome with the efi 460 and e4od at 17k lbs.

Actually got up to 70 mph a couple times, did most of the trip from at 60 mph though.

Being tuned for sea level with the carb and then doing much driving above 5k feet, pretty well ran rich by 2 points, was 10 instead of 12 etc everywhere except at wot then would be low 12s instead of high 12s. Vacuum gage wouldn't go below 8 inches above 6k feet, but maybe that is due to the gage reference. I dunno. Regardless, it drove well everywhere.

Being fully loaded meant any tip in lean from the carb went un noticed, so slow to start that it was drawing full steam by the time it moved in any meaningful way

 

[Provience]

Welp, time to address the trailer at least it made the trip! Sure didn't have another 1k miles left in it and it was exciting just turning it around in the driveway